Locking-screw.



No. 824,017. l PATENTE) JUNE 19,1906.

APPLICATION FILEDJ'AN. 2; 1904.

UNITED STATES V PATENT OFFICE lFREDERICK J. HERDLE, F CHICAGO, ILLINOIS.

menne-SCREW.,

Specification of Letters Patent.

Patented June 19, 1906.

Application filed January 2, 1904. Serial No. 187.526.l

To all whom it mayl concern,.-

Be it known that I, FREDERICK J. HERDLE, a citizen of the United States,residing at Chicago, in the county of Cook and State offIlli- 4noIs,have invented certain new and useful screws soon become loosened andwork out of their seats in the substance in are embedded.

Itis the object of this invention to produce which they y a meansorlocking a' screw iirmly'in. its sur- In the embodiment herein shownof\this 'roundin material, which-lookin means may be with rawn when itis desirab e to remove the screw for any purpose, but which means isroof against accidental displacement.

n theaccompanying drawings, Figure lis .Y a perspective view of a screwembodying a portion ofrny invention. Fig. 2 is a sec-Y tional viewshowi-ng -said screw in use Fig. 3 is a top .lan view of this improvedlockingthe invention vas applied to a lagrscrew.

. invention Iprovide a wood-screw A, having closely in its stem a- E A',which groove passes through the head A2 of the screw and communicateswith the slot As in said head. The groove A near its upper endthat is tosay, near the head Az of the screw--is deeper than at its lower end,

which is to provide a seatfor thelocking-nail 4o lto be lnext described,when the screw ts within an openingin metal or other hard or brittlematerial.l i

B is a loc 'ng-nail intended tobe driven into vthe'groove A in theside-ofthe screw af- V specially madeto conform to the groove A ter 'thelatter is, seated.A This nail may be or it-may be a common nail with ahead B .narrow enough to" enter thet slot A of the screw and having theundercut edges'B", by y g. 4 isa section on dotted line 4 4 .'of Fig. 2.Fig. 5 is a sectional view showing ongitudinally-extending groove meansof which the nail may be grasped with suitable pliers y(not shown) andwithdrawn from its seat in the groove A As hereinbefore stated, thegroove becomes shallower toward its lower end, and when the4 nail B isdriven into said groovethe point of said nail is gradually turnedoutward, .and Whenit encounters the extreme lower end of ythegroove A'the conformation ofthe latter is such as to turn the point of the nailquite abruptly into the-surrounding wood or other `substance in whichthe screw is seated.

When it is desirablek to 'release the locking means, the nail is removedin any suitable manner, as by a pair of narrow pincers, whereupon thescrew maybe readily withdrawn.

In Fig." 5 the invention is shown initsadap-` tation to a lag-screw. "Inthis figure, C repre-v sents the lag-screw body, C the groove therein,and C2 the head.

Obviously the constructions hereinbefore described admit of furthermodifications without departing 4from the spirit and scope of myinvention, wherefore I desire to have it understood that I do not limitmyself to the precise details shown and' described: l

I claim as my inventiona wood-screw having a longitudinal groove in In alocking wood-screw, 1n combination,

itsside extending from and through its head toward its point, said screwhaving a slot in its head for the reception of a driver, the upper end,of said' longitudinal groovev opening into said slot, and the bottom ofsaid groove at its lower end turning out abruptly; and a locking-nail ofgreater length than said roove and having a point adapted to be bent yimpingem'ent u on the lower end walllof said groove, where y when saidnail is driven into said groove the point of the nail will be forcedinto thel surroundingl wood and thus lock said screw a ainst withdrawal,said nail having a heada apted to lie Within the slot in the head of thescrew.

' .FREDERICK 'J.,II IERDIIE., y

Witnesses; T. M..BA'1Es, GEORGE L. CHINDAHL.

